The objectives of this research are to determine those factors which influence the kinetics of ligand-binding in hemoglobins and myoglobins, to correlate binding studies with association-dissociation kinetics of the proteins, to elucidate and quantitate the kinetic features in dimeric co-operative hemoglobins and myoglobins, and to investigate the inter-chain interaction energies and how they are coupled to ligand-binding energetic parameters. A wide variety of systems are to be investigated, including human hemoglobins, mammalian myoglobins, invertebrate dimeric and polymeric hemoglobins, and single crystals of vertebrate hemoglobins. The crystal kinetics will be followed in a specially-constructed microspectrophotometer. Light-scattering changes associated with ligand-binding will be followed in a dual light-scattering-absorbance stopped-flow of our design. Ligand-binding studies for the ligand-bound conformation will be carried out by flash-and dye-laser photolysis. Whenever feasible, the proteins will be isolated using preparative isoelectric-focusing, and kinetic measurements will then be conducted on individual bands. All of the kinetic devices have been interfaced to an on-line mini-computer which provides real-time data acquisition, reduction, and analysis. After having obtained data of high precision through the use of purified protein preparations and computerized data acquisition, we will be interested in seeking structure-function correlations among the various hemoglogins, and will combine equilibrium and kinetic data so as to obtain a quantitative description of ligand-binding for co-operative dimeric systems.